TUESDAY, Jan. 7, 2014 (HealthDay News) -- Premature babies who cry a lot may be more likely than other preemies to have behavior problems by the time they reach preschool, a new study suggests.

Experts said the reasons for the finding are not certain, and no one knows whether "interventions" to soothe preemies' crying would ward off behavior issues later.

"In many ways, this study raises more questions than it answers," said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children's Medical Center in New Hyde Park, N.Y.

Parents and pediatricians should pay attention to preemies' "excessive crying," said Adesman, who was not involved in the study.

But that won't necessarily lead to a better-behaved preschooler, he added.

For the study, child psychiatrist Riikka Korja and colleagues at Turku University Hospital in Finland followed 180 premature infants delivered at their hospital. The babies were all born at a very low birth weight -- less than 1,500 grams, or 3.3 pounds.

Parents kept diaries to record how often, and for how long, their baby cried each day. Then when their child was 3 or 4 years old, they completed standard questionnaires that gauge behavior issues -- such as rule-breaking and problems getting along with other kids.

Overall, the study found that the more infants cried each day, the higher their scores on problem behaviors at preschool age. That link was especially strong when the researchers focused on crying at the age of 5 months -- which is beyond the age where "colic" (crying for hours a day) is common.

At 5 months, babies in the study were crying for a little more than an hour per day, on average. According to Korja's team, the findings suggest that 5-month-olds who are crying more often than the norm may have higher odds of behavior problems later.

The findings were published online Jan. 6 and in the February print issue of Pediatrics.

But another expert cautioned that prolonged crying does not mean your child is doomed to have serious behavior issues.

Most kids in the study had behavioral scores that were within the range of "normal," said Dr. Katherine Steingass of Nationwide Children's Hospital in Columbus, Ohio.

"Just because your baby is crying a lot does not mean they're going to have significant behavioral problems," said Steingass, who was not involved in the study.

And why would infants' crying be related to behavior at preschool age? It's not clear, but Korja's team suggests one possibility: Infants who cry a lot may have underlying "regulatory difficulties." And when they get older, they may still find it hard to control their behavior when they're distressed.

Steingass said that is a plausible explanation.

It's also possible, she noted, that certain parents are prone to perceiving problems. In this study, moms who were more stressed tended to report more behavior issues. Still, when the researchers factored in mothers' reported stress levels, the link between infant crying and preschool behavior remained. While the study found an association between excessive crying and later behavior problems, it did not establish a cause-and-effect link.

All babies cry and fuss, of course, so parents might be left wondering how much is "too much."

There's no universal definition, said Dr. Daniel Coury, who heads developmental and behavioral pediatrics at Nationwide Children's. But babies might be considered "colicky" if they are crying for more than three hours per day, he said.

Parents can take steps to help soothe a colicky baby, Coury said -- like holding and rocking, or swaddling. Some babies are calmed by a ride in the car or steady background noise, like a fan or a "white noise" machine.

Both Coury and Steingass said that if parents are worried that their baby is crying too much, they should talk to their pediatrician. "Often, reassurance from your doctor is very helpful," Coury said.

According to the U.S. National Institutes of Health, about 20 percent of infants develop colic, which is usually at its worst between the ages of 4 and 6 weeks. It typically goes away at around 3 months of age.

Adesman agreed that talking to your pediatrician about colic is important, but stressed that more research is needed before it can be seen as a way to influence children's behavior later in life.

And since this study focused on low birth weight preemies, it's not clear if the results apply to full-term babies, Adesman added.

However, Korja's team writes, some past research on full-term infants has linked excessive crying beyond the age of 3 months to hyperactivity and behavior issues later on.